Infusion ports for the infusion and/or withdrawal of fluids from a patient are well-known, secured to the proximal end of an implanted catheter. These ports are typically used for drug infusion or small amounts of blood withdrawal, where large flows of fluid are not required. Implantable venous access ports have the advantage that they can remain within the patient for prolonged periods of time, permitting multiple use and decreasing the risk for associated infection. The ports are assemblies of a needle-impenetrable housing with a discharge port in fluid communication with the catheter and the reservoir or chamber within the port housing, and provide a subcutaneous self-sealing septum that defines an access site for multiple needle sticks through the covering skin tissue of the patient, through the septum and into the reservoir, without the need to continuously search for new access sites. The septum is comprised of material such as silicone elastomer that self-seals each time as a needle is withdrawn. Examples of such ports are disclosed, for example, in U.S. Pat. Nos. 4,704,103; 4,762,517; 4,778,452; 5,185,003; 5,213,574 and 5,637,102; and 6,113,572. Another catheter infusion port is disclosed in U.S. Patent Publication No. US 2006/0184142 published on Aug. 17, 2006 (Ser. No. 11/335,369 filed Jan. 19, 2006).
Some ports are in use, known as dual ports or multi-ports. These provide two or more septa and internal chambers, all corresponding to different lumens of the attached catheter via respective separate discharge ports or alternatively, separate passageways in a single stem for communication with separate lumens of a dual or multi-lumen catheter, such as in U.S. Pat. No. 5,360,407.
Typically, a port housing includes a base and a cap that together cooperate to secure the needle-penetrable septum within the assembly by compressing a seating flange of the septum in a seat of the housing base. The housings of many such ports are bonded (or welded) together, with fixtures holding the cap to the base as the bonding agent dries (or as welding is performed), to compress the septum flange to assure compression of the septum flange after manufacturing is completed. One manner of securing a cap to a base is disclosed in U.S. Patent Publication No. US 2007/0270770 published on Nov. 22, 2007 wherein the housing cap and base mechanically self-retain to compress the septum flange as the bonding agent cures. In this port, horizontal rib segments are formed on either the interior surface of the cap or the exterior surface of the base, while the other thereof provides grooves for the rib segments, such that the cap is snap-fitted to the base by this fastening arrangement to compress the septum flange between the cap and base, thus eliminating the necessity of using fixture tooling during manufacturing while the bonding agent dries.
It is desired to provide a venous access port assembly that is assuredly secured together in an assuredly sealed manner.